Synthetic lubricating oils



Patented Feb. 1 1, 1936 UNITED STATES SYNTHETIC Frederick H. MacLaren, signor to Standard Oil LUBRIOATIN G OILS Calumet City, Illnes- Company, Chicago, 11].,

a corporation of Indiana No Drawing. Application December 1, 1932,v

Serial No 9 Claims.

This invention relates to lubricating oils and it pertains more particularly to lubricating oils synthesized from materials which have little or no value as lubricants in themselves.

It is desirable that certain oils, particularly lubricating oils subjected to a wide variation in operating temperatures and oils used in pressure transmitting systems, such as hydraulic brakes, have a low susceptibility of viscosity change with temperature or a high viscosity index. The term viscosity index as used in this specification is defined in an article by Dean &'Davis, published in Chemical and Metallurgical Engineering, vol. 36, page 618, and now quite generally understood in the petroleum art. It is a convenient way of expressing in figures, the tendency of an oil to undergo 'change of viscosity with change of temperature. Oils of the Pennsylvania type are assigned a viscosity index of 100 while oils of the Gulf coastal type are rated as zero. Oils falling inside and outside of this range are rated by their relation to these two base oils in this respect. Oils having a high viscosity index do not thin out at high temperatures or resist flow at low temperatures to the same extent as oils with low viscosity index. An object of my invention is to provide an improved synthetic lubricating oil having an extremely high viscosity index.

Paramn wax has a high viscosity index but is not suitable for use as a lubricant because it is a solid at ordinary temperatures and it also has a low viscosity. One object of my invention is to provide a method of converting paraflin wax into an improved lubricant of the type above described which will I.) liquid at ordinary temperatures. A further object is to provide a synthetic lubricating oil of relatively light color, and one in which the color will be stable. A further object is to provide a lubricant which will be resistant to oxidation and sludge formation. Other objects will be apparent as the detailed description of my invention proceeds.

Attempts have heretofore been made to prepare synthetic lubricating oils from various raw materials, particularly from cracked heavy hydrocarbons and waxes. For instance, the olefines obtained by the cracking of paraffin wax have been condensed with aluminum chloride to produce synthetic lubricants. In this case, however, relatively low yields of oil were obtained and an oil was produced having a viscosity of about 100-125.

I have discovered that when the condensation of chlorinated paraflln is carried out in the presence of a polynuclear aromatic compound, such as diphenyl, and the proportions ofaluminum chloride and the conditions of the reaction are properly regulated a condensation product will result which has a viscosity index as high as 180. a pour point as low as 60 F., an A. P. I. gravity at 60 F. of about 21, a desirable light color, and an unusual resistance to sludging. Furthermore, I obtain yields as high as 85%. In this application the term polynuclear aromatic compound 10 shall refer to those compounds containing a plurality of aromatic nuclei in contradistinction to the condensed ring type of compounds such as naphthalene, anthracene, phenanthrene, etc. The invention will be more clearly understood from the following description of preferred embodiments thereof.

As a. preferred example of my invention I will describe the preparation of synthetic oil by the use of the following fomula: Chlorinated wax (23.4

chlorine) 100 parts by weight Diphenyl 5 parts by weight Aluminum chloride 15 parts by weight Naphthaabout 200-300 parts (enough to maintain the reacting mixture in solution) The diphenyl and the aluminum chloride are dissolved in the naphtha and the solution is raised to a temperature of about 130-140 F. The chlorinated wax is then gradually added to the hot solution and the reaction which is quite vigorous is allowed to run for a period of time, between one and ten hours; it is impossible to specify the time of reaction which will be'applicable to all sorts of material, but the chemist can easily tell by inspection when the reaction is complete. In the present instance the reaction is substantially complete in about two hours. The mixture is then allowed to settle and the alumi- 40 num chloride sludge is withdrawn from the oily layer which is thereafter distilled to remove the naphtha. In this particular case I obtain a yield ofabout 84% of a light colored oil having a viscosity of 210 F.'of 63 seconds Saybolt, a viscosity at 130 of 145 seconds and a viscosity at 100 F. of 220 seconds. This oil has a viscosity index of 180, an A. P. I. gravityat 60 F. of 21 and a pour point of about 60- F. In case the sludge does not separate readily from the reaction mixture, hexane or other light solvents may be added to increase the dilution.

By using twice as much diphenyl in the above process and maintaining all of the other variables constant I obtain a yield of 85% of an 'oil having a viscosity at 210 F. of 86 seconds, at 130 F. of 279 seconds and at 100 F. of 550 seconds. It has a viscosity index of 130, an A. P. I. gravity at F. of 20 and a pour point of 60 F.

By .further increasing the amount of diphenyl I find that the viscosity index falls ofi, the yields become less and the duality of the product is. greatly reduced. In general, I do not use less than 5% nor more than 25% of the diphenyl in the mixture, based on the weight of chlorinated hydrocarbon wax. When unduly large amounts of aluminum chloride are used, a resinous product is obtained instead of a light oil. Preferably I use about 5 to 15 parts of aluminum chloride per 100 parts of chlorinated wax, and maintain the reaction temperature at about 130-140 F. in naphtha solution. Under these conditions I find that the reaction is complete usually in about three or four hours. Temperatures between and 250 F. may be employed, and as little as 1% AlCls may be used.

In the above preferred example I described the use of a chlorinated paraffin wax, the wax having a. melting point of about 130 F. and being chlorinated to contain about 23.4% chlorine. It should be understood that this is merely one example of a halogenated hydrocarbon wax and I may also use chlorinated ceresin, petrolatum, ozokerite, etc. The amount of chlorine may be varied from about 5 or 10% to 25 or 30%.

Instead of diphenyl I may use other polynuclear aromatic compounds such as ditolyl, particularly ortho and para, diphenyl benzene, diphenyl and triphenyl methane, dibenzyl, phenyl tolyl, and the like. Diphenyl appears to be far superior, however, to any of the compounds which have so far been tested. It should be particularly noted that by using diphenyl with aluminum chloride to condense the chlorinated waxes or heavy hydrocarbons I obtain unprecedented yields of synthetic oils. The oil has a relatively low pour point and an exceptionally high viscosity index, and it also has a pale color and exceptionally high resistance to sludge formation. I have been unable to determine the cause of the remarkably high viscosity index of oils produced by the condensation of chlorinated wax and polynuclear compounds. In general, aromatic oils and other aromatic substances are characterized by low viscosity index, i. e., high susceptibility to viscosity change with temperature. It is possible that this undesirable effect of aromatic nuclei in lubricating oils is in some way diminished by their simple combination as inpclynuclear hydrocarbons. It is probably also true that polynuclear hydrocarbons condense with chlorinated paraffins to give oils of higher viscosity with a lower degree of condensation and polymerization than is the case with simple aromatic nuclei. While I have described in detail a preferred embodiment of my invention it should be understood that I do not limit myself to any of said details except as defined by the following claims which should be construed as broadly as the prior art will permit.

I claim:

1. The method of making synthetic oils substantially free from resinous and pour point depressor materials which comprises condensing chlorinated hydrocarbon wax and about 5 to 25 parts of diphenyl in the presence of about 1 to 15 parts aluminum chloride per parts of chlorinated wax.

2. The method of making synthetic oils substantially free from resinous and pour point depressor materials which comprises condensing halogenated hydrocarbon wax and about 5% of diphenyl in the presence of about 15% of aluminum chloride.

3. The method of preparing a synthetic oil substantially free from resinous and pour point depressor materials which comprises condensing a chlorinated hydrocarbon wax with a small amount of diphenyl in the presence of a small amount of aluminum chloride in an organic solvent.

4. The method of claim 3 wherein the condensation is effected at a temperature of about to F.

5. A synthetic oil substantially free from resinous and pour point depressor materials having a viscosity index between 130 and 180, a pour point of about 60 F. and an A. P. I. gravity of about 20 to 21.

6. The process of making high viscosity index lubricating oil substantially'free from resinous and pour point depressor materials comprising reacting a chlorinated hydrocarbon wax with ditolyl in the presence of a condensing catalyst.

7. The process of making high viscosity index lubricating oil substantially free from resinous and pour point depressor materials comprising reacting a chlorinated hydrocarbon wax with diphenyl methane in the presence of a condensing catalyst.

8. The process of making high viscosity index lubricating oil substantially free from resinous and pour point depressor materials comprising chlorinating paraffin wax to a chlorine content of between 5 and 30%, treating said chlorinated wax in a. naphtha solution from 5 to 25% of its weight of diphenyl in the presence of l to 15 parts of aluminum chloride per 100 parts of chlorinated wax at a temperature between 80 and 250 F.,allowing the reaction mixture to separate into two layers after completion of the reaction, discarding the aluminum chloride sludge layer and recovering the lubricating oil product from the naphtha layer by evaporation of the naphtha therefrom.

9.. The method of making synthetic oils substantially free from resins and pour point depressor materials, which method comprises chlorinatinghydrocarbon wax to a chlorine con tent of about 10 to 25% and treating said chlorinated wax with about an aromatic compound of the class consisting of diphenyl, ditolyl, diphenyl methane, dibenzyl and phenyl tolyl, in the presence of 1 to 15 parts of aluminum chloride per 100 parts of chlorinated wax at a temperature between 80 and 250 F. and separating the resultant synthetic oil from aluminum sludge and impurities.

FREDERICK H. MACLAREN.

5 to 25% of its weight with 

